As a main server for a main enterprise system or the like, a composite computer system, a so-called blade server has been known. The blade server is a high density server in which a plurality of CPU blades each having functions such as a CPU, a memory, a hard disk, and the like provided on one circuit board are mounted according to need in a casing called “enclosure”.
In some blade servers, a Tag-VLAN (Virtual Local Area network) function which sets a NIC (Network Interface Card) mounted on the CPU blade logically as a plurality of NICs is provided.
When the Tag-VLAN function is used, the number of logic NICs prepared for one NIC driver serving as a device driver of the CPU blade and VLAN-IDs corresponding to the respective logic NICs are set from a management terminal connected to the blade server.
Subsequently, on a side of a Ethernet switch provided on the blade server, the enable setting of the Tag-VLAN to a port physically connected to the NIC on which the Tag-VLAN setting has been performed, the setting of corresponding VLAN-ID and the setting of a priority, if necessary, are performed.
Incidentally, a method for setting a VLAN in such a blade server has been described in IBM BladeCenter 4-Port Gb Ethernet Switch Module Installation and User's Guide” issued by JAPAN IBM CORP. in April, 2004.